The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

ELECTRIC TIME-BALL.
CHAPTER LIII.
Utility of Electric Time-Balls for Correction of Chronometers-Nelson's Monument and Time-Ball.
UTILITY OF ELECTRIC TIME-BALLS.
IN America, we have a National Observatory, and though it
has had but a few years' existence, its fame has spread throughout the civilized world, and added new lustre to our glory;
but we have no time-balls in our maritime cities, to indicate
the hour and the movement of the pendulum at Washington,
in our National Observatory.
In England, at an early day in the history of electric telegraphing, the science was employed as an auxiliary at the
Greenwich Observatory, in the determination of longitude, the
movements of the stars and other heavenly bodies, and for the
diffusion of chronometer time throughout the country. The
astronomer royal, in concert with the electric telegraph
companies, announces an hour of each day, by the fall of
electric time-balls from elevated positions, in different parts of
the country. The moment the ball at Greenwich falls, those
in other cities fall. There is one of these balls on the Strand,
near Charing Cross, in London, and it serves a good purpose
in the correction of chronometers, whether in the hands of the
mariner, the merchant, or the manufacturer. Persons can
regulate their own timepieces, without the aid of the watchmaker. Besides this arrangement for giving correct time, I
noticed at Greenwich, an electric clock, in connection with the
leading telegraph office in London, by wires; signals are transmitted from the observatory to Lothbury, the telegraph office,
every hour of the day. The same signals are made at the
office on the Strand before mentioned, and they are also sent
to Dover, Tunbridge, Deal, and other places. At specific times
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